Compliant pivot socket for automotive steering

ABSTRACT

A pivot socket of the present invention incorporates a stud shaft component having a partially spherical head portion disposed within a housing cavity, and an axial pin extension extending upward into the cavity therefrom. The partially spherical head portion seats against a partial spherical bearing surface disposed within the housing cavity, and the axial pin extension is enclosed within a resilient cushion. During use, lateral and axial loads imparted on the stud shaft are transformed into radial and axial component forces at the bearing surfaces. The radial force components are distributed to the interior walls of the housing cavity, while the axial force components are transferred axially through the resilient cushion to the end closure components secured to the housing. Little or no lateral force components are transferred to the resilient cushion from lateral loads imparted on the stud shaft, thereby reducing wear on the pivot socket components and extending the useful life thereof.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This is a divisional application related to U.S. patentapplication Ser. No. 09/566,288 filed May 5, 2000, from which priorityis claimed.

BACKGROUND OF THE INVENTION

[0002] This invention relates to the design of movable sockets, forexample, ball joints as used in automotive steering and suspensionsystems, and more particularly, to a movable socket configured with aspherical or part-spherical bearing surface and a projecting pin studrestrained within an elastomeric or spring-centered compliance bearing.The movable socket of the present invention is additionally configuredto have increased durability under conditions of high load andmisalignment and to be assembled using conventional techniques. Whilethe present invention is described in detail with respect to automotiveapplications, those skilled in the art will recognize the broaderapplicability of the invention.

[0003] Conventional ball joints, and other movable sockets are used, forexample, in automotive steering and suspension applications. The socketscomprise a housing having a circular cylindrical internal surface, aball stud with a part-spherical ball head contained in the housing, anda synthetic resin or sintered alloy bearing member supporting the ballhead within the housing. These components are commonly installed intothe housing through a posterior opening, with the ball stud extendingoutward through an axially disposed anterior opening of a smallerdiameter than the ball head. Traditionally, the posterior opening isclosed by means of a cover-plate, spun, swaged, or welded in place. Oncesecured in place, the cover-plate presses on the bearing member eitherdirectly or indirectly through a resilient rubber intermediatecomponent.

[0004] Several ball joint designs incorporating a projecting pin fromthe upper surface of the ball stud are shown in the prior art. Thesedesigns are intended to limit angular movement of the stud relative tothe housing in which it is contained.

[0005] U.S. Pat. No. 3,790,195 issued to Edward J. Herbenar on Feb. 5,1974 discloses a preloaded socket joint for an automotive steeringlinkage. The '195 socket joint is primarily for rotational movement witha stud projecting from an internal cavity housing and having apart-spherical bulged section received in the housing and seated againsta spherical face seat adjacent the projecting point of the stud from thehousing. The stud further includes an axial extension beyond the halfsphere within the housing which is received in a bearing with aresilient member entrapped between the wall of the cavity and thebushing. The opposite end of the housing cavity from the point ofprojection is closed by a cap which applies a preload to the axial endof the stud within the cavity and to the resilient member. As can beseen in FIG. 1 of the '195 patent, all axial loads on the stud aretransferred either directly through the stud itself to the cap whichcloses the housing, or through the bushing and resilient member to thecap.

[0006] U.S. Pat. No. 3,945,737 issued on Mar. 23, 1976, also to EdwardJ. Herbenar discloses a modification of the socket joint shown in the'195 patent. The '737 pivot joint provides a housing with apart-spherical bearing seat at one end thereof, a recessed closure capsecured in the other end thereof, and a stud having a shank projectingfreely into the housing with a head tiltable on the seat. The studfurther includes a tapered pin depending from the head and bottomeddirectly on the closure plate together with an axially split rubberbushing surrounding the pin and snugly seated in the housing. A weartake-up member between the closure plate and the bushing urges thebushing toward the head of the stud, and a ring surrounding the recessof the closure plate limits the tilting of the stud on the bearing seat.In this design, the compressive loads of the stud and the angulationloads of the stud are taken by the same member, i.e. the axially split,resilient bushing with a tapered bore. Thus, the design inhibits freedomin selecting an axial preload independently of angulation considerationsand vice-versa.

[0007] U.S. Pat. No. 5,597,258 issued to Kincaid et al. on Jan. 28, 1997discloses a preloaded pivot joint with a stud capable of rotation andangulation. The preloaded pivot joint is designed such that differentinternal components transfer the respective lateral loads, axialcompression loads, and angulation loads experienced by the stud.Specifically, as seen in FIG. 1 of the '258 patent, the studincorporates a hemi-spherical portion for transferring lateral loads toa fixed bearing seat within the stud housing, a concentric convex tipfor transferring compressive (axial) loads directly to a spring biasedbearing seat, and a cylindrical extension between the hemi-sphericalportion and the convex tip for radially transferring angulation loads toa hardened cylindrical metal ring of a resilient composite bushing.

[0008] Each of these prior art pivot sockets includes compliancecomponents formed of a resilient material such as rubber, polyurethane,and the like, which surrounds a projection pin portion of the stud andwhich transfers some form of loading from the stud to the housing.Accordingly, it is highly advantageous to develop a preloaded pivotjoint wherein a single compliance component transfers both axial andangulation loads to either the hardened housing walls or the end closurecomponents, limiting the movement of the stud, but which does not carrylateral loads, reducing wear on the pivot socket components andextending the useful life thereof and which provides freedom inselecting an axial preload independently of stud angulationconsiderations.

BRIEF SUMMARY OF THE INVENTION

[0009] Among the several objects and advantages of the present inventionare:

[0010] The provision of a pivot socket employing a lowerpartially-spherical bearing surface to seat a stud having an axialextension within a housing cavity, and further employing a resilientcomponent to surround the axial extension and to transfer axial loadcomponents from the bearing surfaces to end closure components;

[0011] The provision of the aforementioned pivot socket wherein theresilient component experiences little or no direct radial force whenlateral forces are imparted to the stud;

[0012] The provision of the aforementioned pivot socket wherein the studincludes a partially spherical portion configured to seat against thelower partial spherical bearing surface;

[0013] The provision of the aforementioned pivot socket wherein thelower partial spherical bearing surface transfers lateral loads radiallyand axially from the partially spherical stud portion to the housing;

[0014] The provision of the aforementioned pivot socket wherein apreload component transfers axial loads stud portion axially to theresilient component surrounding the axial extension of the stud;

[0015] The provision of the aforementioned pivot socket wherein theresilient component surrounding the axial extension of the stud extendsfrom the end closure components to adjacent an upper surface of thepreload component;

[0016] The provision of the aforementioned pivot socket wherein apreload component is interposed between the resilient component and theupper surface of the partially spherical stud portion;

[0017] The provision of the aforementioned pivot socket wherein theresilient component acts alone to provide both the axial preload betweenan upper spherical bearing and the lower partially spherical bearing, aswell as providing resistance to angular displacement of the stud member;and

[0018] The provision of the aforementioned pivot socket wherein theconfiguration of the resilient component permits assembly of the pivotsocket using conventional methods.

[0019] Briefly stated, a pivot socket of the present inventionincorporates a stud shaft component having a part-spherical head portiondisposed within a housing cavity, and an axial pin extension extendingupward into the housing cavity. The part-spherical head portion isseated against a lower partial spherical bearing surface disposed withinthe housing cavity, and the axial pin extension is enclosed within aresilient cushion. During use, lateral or axial loads imparted on thestud shaft are transformed into radial and axial component forces at thebearing surface. The radial force components are transferred primarilyto the interior walls of the housing cavity, while the axial forcecomponents are transferred axially through the resilient cushion to theend closure components secured to the housing. Little or no radial forcecomponents are transferred to the resilient cushion from lateral oraxial loads imparted on the stud shaft, reducing wear on the pivotsocket components and extending the useful life thereof.

[0020] The foregoing and other objects, features, and advantages of theinvention as well as presently preferred embodiments thereof will becomemore apparent from the reading of the following description inconnection with the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0021] In the accompanying drawings which form part of thespecification:

[0022]FIG. 1 is a sectional view of an embodiment of a preloaded pivotsocket of the present invention, illustrating an elastomeric cushionresilient member;

[0023]FIG. 2 is a section view of an alternate embodiment of thepreloaded pivot socket of the present invention, illustrating anelastomeric cushion resilient member and Belleville washer preloadconfiguration;

[0024]FIG. 3 is a section view of an alternate embodiment of thepreloaded pivot socket of the present invention, illustrating a conicalspring resilient member;

[0025]FIG. 4 is a section view of an alternate embodiment of thepreloaded pivot socket of the present invention, illustrating a springsteel resilient member and Belleville washer preload configuration;

[0026]FIG. 5 is a section view of an alternate embodiment of thepreloaded pivot socket of the present invention, illustrating anelastomeric compliance bearing resilient member;

[0027]FIG. 6 is a perspective exploded view of the preloaded pivotsocket of FIG. 5;

[0028]FIG. 7 is a section view of an alternate embodiment of thepreloaded pivot socket of the present invention, illustrating anelastomeric compliance bearing resilient member and slipper sleeve.

[0029]FIG. 8A is a section view of an alternate embodiment of thepreloaded pivot socket of the present invention, illustrating a crinkledcoil of spring steel as a compliance bearing resilient member;

[0030]FIG. 8B is a top-down cross sectional view of the alternateembodiment of the preloaded pivot socket of FIG. 8A, illustrating thearrangement of the crinkled coil of spring steel;

[0031]FIG. 9 is a sectional view of a second embodiment of the preloadedpivot socket of the present invention, illustrating an elastomericcushion resilient member; and

[0032]FIG. 10 is a perspective exploded view of the preloaded pivotsocket of FIG. 9.

[0033] Corresponding reference numerals indicate corresponding partsthroughout the several figures of the drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0034] The following detailed description illustrates the invention byway of example and not by way of limitation. The description clearlyenables one skilled in the art to make and use the invention, describesseveral embodiments, adaptations, variations, alternatives, and uses ofthe invention, including what is presently believe to be the best modeof carrying out the invention.

[0035] Turning to FIG. 1, a first embodiment of the pivot joint of thepresent invention is shown generally at 10. The pivot joint includes ahousing 12, within which the various internal components of the pivotjoint are enclosed. Housing 12 is generally cylindrical, with a centralbore 14 of non-uniform radius having a posterior opening 16 and ananterior opening 18. The radius of central bore 14 decreases to define areduced diameter portion 20 at the base of the housing, adjacentanterior opening 18. A circumferential groove 22 is formed in bore 14,adjacent the posterior opening 16. The exterior surface 26 of housing 12may follow the general contour of the central bore 14. In the embodimentillustrated, the surface 26 has an expanded ridge 28 formed in it. Theridge 28 is used for attachment of pivot joint 10 to other components(not shown). As may be appreciated, the ridge 28 also may be adapted forother specific kinds of installations employing threads or otherconnectors (not shown).

[0036] To assemble ball joint 10, a lower bearing 30 sized to fit withincentral bore 14 is seated within housing 12. The lower bearing 30includes a central bore 32 axially aligned with a vertical axis VA ofthe housing, and an outer surface 34 of bearing 30 is designed tocorrespond to the surface 20 in housing 12. The inner surface 35 of thelower bearing 30 is formed in a partially spherical shape to receive astud 36, and may include one or more crenellations or breaks 37 tofacilitate expansion and contraction.

[0037] Stud 36 has a generally cylindrical body 38 and an enlargedspherical ball or head portion 40. To assembly the pivot joint the lowerend of the cylindrical body 38 is passed through central bores 32 and14, such that the lower part-spherical surface 42 of the head portion 40rests on an inner part-spherical surface 35 of lower bearing 30 seatedwithin housing 12. The body 38 may include a uniform diameter upperportion 50 adjacent head portion 40, a tapered central portion 52, and alower portion 54 of a narrow uniform diameter. A passage 55 through thelower portion 54 allows for the connection of additional components (notshown) thereto. The upper portion 50 is sized to fit within the centralbore 32 of bearing 30, with the central portion 52 and lower portion 54extending through the anterior opening 18, externally of housing 12. Itwill be noted that there is a gap G of predetermined width between theanterior opening 18 and the upper portion 50. This gap G or clearancepermits conical and rotational movement of head portion 40 with respectto housing 12 with a predetermined limited range of movement.

[0038] Head portion 40 of the stud 36 additionally includes an upperpart-spherical surface 56 having the substantially same radialdimensions as the lower part-spherical surface 42. When assembled, theupper part-spherical surface 56 and the lower part-spherical surface 42define a generally spherical bearing unit within housing 12 whichpermits the aforesaid conical movement of the stud 36.

[0039] Projecting axially upward from the upper part-spherical surface56 of stud 36 is a cylindrical axial extension or pin portion 58 coaxialwith stud 36 and having a diameter approximately equivalent to that ofthe upper portion 50 of stud 36. The length of the pin portion 58 isselected such that the face 60 of the pin portion is disposed below thecircumferential groove 22 in the housing 12. Those skilled in the artwill readily recognize that the numerous size configurations for thestud 36, the head portion 40, and the pin portion 58 are possible, andwill depend upon the particular application for which the pivot joint isutilized.

[0040] Once the lower part-spherical surface 42 of ball portion 40 isseated against the inner surface 35 of the lower bearing 30, an upperbearing 62 having an outer surface 63 sized to fit within the centralbore 14 and an inner part-spherical bearing surface 64 conforming to theupper part-spherical surface 56 of the head portion 40 is seated againstwithin the housing 12, against the upper part-spherical surface 56. Theupper bearing 62 may include a number of resected portions 65 and slits66 for lubrication and to allow for contraction and expansion within thecentral bore 14, so as to conform tightly against the surface 56.

[0041] In the embodiment shown in FIG. 1, a shaped elastomeric cushion68 having a central bore 70 sized to fit around the pin portion 58 ofthe stud 36 is seated against an upper face 72 of the upper bearing 62.The elastomeric cushion 68 may be isolated from the pin portion by meansof a steel sleeve (not shown). The outer diameter of the elastomericcushion 68 is sized to fit within the central bore 14, contacting thehousing 12 and to extend slightly above the circumferential groove 22.To enclose the installed components within the housing, and to apply apredetermined preload pressure to the upper bearing 62 and lower bearing30, an end closure cap 74 is installed within the circumferential groove22 to close the posterior opening 16, partially compressing theelastomeric cushion 68. The end closure cap 74 may be retained withinthe circumferential groove 22 by any conventional means such as welding,spinning, or swaging of the housing 12, and may contain an axiallydisposed grease fitting 75. The compression of the elastomeric cushion68 provides a resilient preload force downward from the end closure cap74 and onto the upper face 72 of the upper bearing 62. The upper bearing62 transfers a portion of the preload force onto the head portion 40 ofthe stud 40 which, in turn, transfers the force axially to the lowerbearing 30 and to the housing 12. This preload force takes up anydimensional slop in the manner in which ball 40 is socketed in thebearings 30 and 62.

[0042] In this configuration, when a lateral force is applied to theportions of the stud 36 which projects from housing 12, the force istransferred radially into the lower bearing 30 and upper bearing 62. Dueto the part-spherical curvature of the inner surfaces of these bearings,and the partially spherical configuration of the head or ball portion 40of stud 36, a portion of the radially transferred force is directedoutward against the housing 12, and a portion of the force is directedaxially upward through the bearing 62 and axially downward through thebearing 30. The axially downward force is received in the lower portionsof the housing 12 against which the bearing 30 is seated. The upperbearing 62 is not restrained against axial upward movement by anyportion of the housing 12. Hence, if unimpeded, the upper bearing 62would move axially upward in response to a lateral force on the stud 36.However, the elastomeric cushion 68 is interposed between the endclosure cap 74 and the upper face 72 of the upper bearing 62.Correspondingly, the component of the lateral force on the stud 36 whichis directed radially upward through the upper bearing 62 is transferredthrough the elastomeric cushion 68 to the end closure cap 74 and thehousing 12.

[0043] In the event a direct axial load is applied to stud 36, it willsimilarly be transferred though the upper bearing 62 to housing 12 andto elastomeric cushion 68 and end closure cap 74. Only when angulationloads are applied to stud 36, resulting in a rocking movement of thehead portion 40 about a central pivot point will cause elastomericcushion 68 to experience radial forces transmitted through pin portion58. By isolating elastomeric cushion 68 from radial forces due to axialand lateral loads on stud 36, the wear on cushion 68 is reduced.

[0044] In a first alternate embodiment of the pivot joint of the presentinvention, shown in FIG. 2, a Belleville washer 76 is interposed betweenelastomeric cushion 68 and upper face 72 of upper bearing 62. Prior tothe closure of central bore 14 by end closure cap 74, Belleville washer76 is in a slightly conical configuration. The preload compression forceapplied through elastomeric cushion 68 by end closure cap 74 when it isseated within circumferential groove 22 to close posterior opening 16deforms the Belleville washer to a substantially planar configuration,increasing the amount of preload force applied to the components withinhousing 12.

[0045] Turning to FIG. 3, a second alternate configuration of the pivotjoint of the present invention is shown, in which elastomeric cushion 68is replaced by a conical compression spring 168. Conical compressionspring 168 is wound such that the lower portion of spring 168 seated onupper face 72 of upper bearing 68 is disposed apart from pin projection58, and seated within a recessed channel or groove (not shown) toprevent radial motion. Alternatively, the lower portion of spring 168contacting upper face 72 may be wound so as to additionally contacthousing 12. Conversely, the upper portion of conical compression spring168 is wound in a smaller diameter, to simultaneously contact endclosure cap 74 and pin portion 58 adjacent face 60.

[0046] During installation, when conical compression spring 168 isenclosed between end closure cap 74 and upper face 72 of upper bearing62, it is compressed to provide a preload force on upper bearing 62,lower bearing 30, and stud 36. As with elastomeric cushion 68, theconical compression spring is configured to transfer axial loadsresulting from axial or lateral forces on stud 36 upward to end closurecap 74 from upper bearing 62. The upper portion of the spring 168 incontact with the pin portion 58 of stud 36 resists radial forcesresulting from any angulation forces on stud 36. Those skilled in theart will recognize that a variety of conical compression springs may beemployed within the scope of the present invention. For example, thenumber of coils in the spring, the thickness of the coils, and theexpansive force of the spring may be varied depending upon theparticular application for which pivot joint 10 is designed.Alternatively, the shape of compression spring 168 may be that of anhourglass, such that the constricted portion of compression spring 168contacts the surface of pin portion 58 approximately midway between headportion 40 and face 60, while the upper coils of compression spring 168are in contact with inner bore 14 of housing 12 and end closure cap 74,adjacent circumferential groove 22. Such an hourglass configuration maybe composed of a pair of conical springs, positioned about pin portion40 with one spring inverted relative to the other.

[0047] Turning to FIG. 4, a third alternate embodiment of pivot joint ofthe present invention is shown wherein conical compression spring 168 isreplaced with a flared tube 268 formed from spring-steel. Flared tube268 is formed with an upper cylindrical portion 270 having a diametersized to contact the surface of pin portion 58 adjacent end closure cap74. A circumferential flange 272 extends radially outward from portion270 to seat against the surface of end closure cap 74. Lower portion 274of flared tube 268 is flared outward in a radially increasing manner toseat against housing 12. In a relaxed state, prior to the installationof end closure cap 74 in circumferential groove 22, flared tube 268 hasan overall length slightly greater than the distance between uppersurface 72 of upper bearing 62 and circumferential groove 22. Seatingend closure cap 74 in circumferential groove 22 compresses flared tube268 against upper face 72 of upper bearing 62, causing lower portion 274to flex and exert a preload force on upper bearing 62, lower bearing 30,and stud 36. To further increase the preload force and to provide for aneven distribution of axial forces between upper face 72 of upper bearing62 and flared tube 268, a Belleville washer 276 may be interposedbetween lower portion 274 and upper face 72. The preload forces exertedby the installation of end closure cap 74 into circumferential groove 22additionally result in a deformation of Belleville washer 276.

[0048] As with elastomeric cushion 68, flared tube 268 is configured totransfer axial loads resulting from axial or lateral forces on stud 36upward to end closure cap 74 from upper bearing 62. Upper portion 270 offlared tube 268 in contact with pin portion 58 of stud 36 resists radialorces resulting from any angulation forces on the stud 36. Those skilledin the art will recognized that a variety of flared tubes 268 may beemployed within the scope of the present invention. For example, thethickness of the tube, and the expansive force of the flare material maybe varied depending upon the particular application for which pivotjoint 10 is designed. Alternatively, the shape of flared tube 268 may bethat of an hourglass, such that a constricted portion (not shown) offlared tube 268 contacts the surface of pin portion 58 approximatelymidway between head portion 40 and face 60, while the upper portion iscontact with housing 12 and end closure cap 74, adjacent circumferentialgroove 22.

[0049] Turning to FIGS. 5 and 6, a fourth alternate embodiment of pivotjoint of the present invention is illustrated wherein elastomericcushion 68 is replaced with an elastomeric compliance bearing 368.Elastomeric compliance bearing 368 is composed of an outer metal ring370 in contact with housing 12, an inner bearing sleeve 372 sized to fitaround pin portion 58, and an intermediate ring 374 of elastomericmaterial disposed between outer ring 370 and sleeve 372. Seated betweenelastomeric compliance bearing 368 and upper face 72 of upper bearing 62is a Belleville washer 378 and a telescoping ring 380. Duringinstallation, Belleville washer 378 is seated against upper face 72 ofupper bearing 62. Next, telescoping ring 380 is placed on Bellevillewasher 378, and elastomeric compliance bearing 368 seated thereon.Finally, end closure cap 74 is installed within circumferential groove22. The installation of end closure cap 74 deforms Belleville washer 378and crushes portions of telescoping ring 380, such that the Bellevillewasher exerts a preload force on upper bearing 62, stud 36, and lowerbearing 30.

[0050] As with elastomeric cushion 68, elastomeric compliance bearing368 is configured to transfer axial loads resulting from axial orlateral forces on stud 36 upward to end closure cap 74 from upperbearing 62. These axial loads are transferred from upper bearing 62through Belleville washer 378 and crushed telescoping ring 380 to outermetal ring 370 of the elastomeric compliance bearing and to end closecap 74. Inner bearing sleeve 372 in contact with pin portion 58 of stud36, and elastomeric intermediate ring 374 resists any radial forcesresulting from angulation forces on stud 36. Those skilled in the artwill recognize that a variety of materials may be utilized to formelastomeric compliance bearing 368 within the scope of the presentinvention. For example, the thickness of outer ring 370 and inner sleeve372 may be varied depending upon the particular application for whichpivot joint 10 is designed. Alternatively, inner sleeve 372 may beeliminated, and the properties of elastomeric intermediate ring 374varied to absorb radial forces directly from pin portion 58.

[0051] Turning next to FIG. 7, a fifth alternate embodiment of thepresent invention pivot joint is shown wherein lower bearing 30 isreplaced with a slipper sleeve 400. Although shown in the context of theembodiment of FIG. 6, slipper sleeve 400 illustrated in FIG. 7 willreadily be understood by one skilled in the art of pivot joint design tobe usable with each embodiment disclosed herein. Utilizing slippersleeve 400 in place of lower bearing 30 permits the pivot point of stud36 to sit lower in housing 12, such that a lower profile socket can beutilized.

[0052]FIGS. 8A through 10 illustrate alternate embodiments of thepresent invention pivot joint wherein upper bearing 62 and upperpart-spherical surface 56 are eliminated, and the cylindrical axialextension or pin portion 58 is elongated. In place of upperpart-spherical surface 56, a flat radial upper surface 402 directlyreceives Belleville washer 378 and a first flat washer 380.

[0053] Turning specifically to FIGS. 8A and 8B, a sixth alternativeembodiment of the present invention pivot joint is shown whereinelastomeric cushion 68 is replaced with a resilient member comprising acorrugated or crinkled coil compliance bearing 410 formed from sheetsteel. Crinkled coil compliance bearing 410 includes a number ofradially orientated peaks 412 and valleys 414, and is spiral wound aboutaxial stud 58 such that each peak 412 on a first portion of spiral woundcrinkled coil compliance bearing 410 is radially aligned, and in contactwith, a valley 414 on a second portion of spiral wound crinkled coilcompliance bearing 410. Those skilled in the art will recognize thatalternative windings of crinkled coil compliance bearing 410 arepossible, and may include the use of two or more concentric rings (notshown) of crinkled coil compliance bearings arranged such that peaks 412on a first ring are radially aligned, and in contact with, a valley 414on a second ring. Seated between crinkled coil compliance bearing 410and flat radial surface 402 is Belleville washer 378 and first flatwasher 380. During installation, Belleville washer 378 is seated againstflat radial surface 402. Next, first flat washer 380 is placed onBelleville washer 378, and crinkled coil compliance bearing 410 seatededge-wise on the upper surface of first flat washer 380. A second flatwasher 415 is positioned on the upper edge of crinkled coil compliancebearing 410, and a telescoping ring 416 is seated thereon. Finally, endclosure cap 74 is installed within circumferential groove 22. Theinstallation of end closure cap 74 deforms Belleville washer 378 andcrushes portions of telescoping ring 416, such that the Bellevillewasher exerts a preload force on flat radial surface 402, stud 36, andlower bearing 30. Also shown in FIG. 8A is a dust cover 420 secured tothe lower portion of the housing, surrounding stud 36. Dust cover 420may be constructed from any flexible material to provide a protectiveenclosure for stud 36 and lower portion of the housing.

[0054] As with elastomeric cushion 68, crinkled coil compliance bearing410 is configured to transfer axial loads resulting from axial orlateral forces on stud 36 upward to end closure cap 74 from upperbearing 62. These axial loads are transferred from flat radial surface406 through Belleville washer 378 and first flat washer 380 to crinkledcoil compliance bearing 410 and up to end closure cap 74 through secondflat washer 415 and telescoping ring 416. The contacting peaks 412 ofcrinkled coil compliance bearing 410 resist any radial forces resultingfrom angulation forces on the stud 36 by resiliently deforming. Lateralloads on stud 36 are transformed into a axial forces by the interactionof lower bearing 30 and stud 36, and are transferred to end closure cap74 through crinkled coil compliance bearing 410. Those skilled in theart will recognize that a variety of materials may be utilized to formcrinkled coil compliance bearing 410 within the scope of the presentinvention. For example, the resilience of the sheet steel may be varieddepending upon the particular application for which pivot joint 10 isdesigned. Alternatively, the number of peaks 412 and valleys 414, aswell as number of spiral windings of crinkled coil compliance bearing410 may be varied to absorb radial forces directly from pin portion 58.

[0055] Turning specifically to FIGS. 9 and 10, a seventh alternativeembodiment of the present invention pivot joint is shown wherein aresilient member comprising an elongated elastomeric cushion 468 restson the upper surface of first flat washer 380. Elongated elastomericcushion 468 surrounds the length of the cylindrical axial extension orpin portion 58, and is secured between the inner surface of the housingdefining central bore 14 and the exterior surface of pin portion 58 byan interference fit. As with elastomeric cushion 68, elongatedelastomeric cushion 468 is configured to transfer axial forces resultingfrom axial or lateral loads on stud 36 upward to end closure cap 74 fromflat radial surface 406, however, the greater surface area of theelongated elastomeric cushion 468 permits the transfer of greater loadswithout permanent deformation or damage. These axial loads aretransferred from flat radial surface 406 through Belleville washer 378and first flat washer 380 to elongated elastomeric cushion 468 and up toend close cap 74 through second flat washer 415 and telescoping ring416. Elongated elastomeric cushion 468 additionally resists any radialforces resulting from angulation forces on stud 36 by resilientlydeforming, allowing only minor freedom of movement of stud 36. Thoseskilled in the art will recognize that a variety of materials may beutilized to form elongated elastomeric cushion 468 within the scope ofthe present invention.

[0056] In view of the above, it will be seen that the several objects ofthe invention are achieved and other advantageous results are obtained.Several embodiments are shown wherein the internal components of a pivotjoint surrounding a partially spherical head portion of the studtransfer lateral and axial forces exerted on the stud axially to the endclosure cap of the housing through internal components other than thestud itself. Simultaneously, these internal components are capable ofproviding a radial resistance to angulation forces applied to the studand transferred to the components through a pin projection on the upperend of the stud within the housing. As various changes could be made inthe above constructions without departing from the scope of theinvention, it is intended that all matter contained in the abovedescription or shown in the accompanying drawings shall be interpretedas illustrative and not in a limiting sense.

1. A preloaded pivot joint assembly comprising: a housing having anaxis; a stud having a part-spherical head portion retained within thehousing, a shaft portion projecting axially from the housing, and a pinportion projecting axially within the housing; at least one bearingdisposed within said housing and having part-spherical bearing surfaces,said bearing surfaces socketing said part-spherical head portiontherewithin and permitting limited spherical and rotational movement ofsaid stud with respect to said housing within a limited range; and anelastomeric cushion disposed within said housing, said elastomericcushion biasing one of said bearings against said spherical head portionto accommodate axial forces therefrom, said elastomeric cushion furthersurrounding said pin portion to accommodate radial forces therefrom. 2.The preloaded pivot joint assembly of claim 1 wherein an annular preloadmember is disposed between said elastomeric cushion and said biasedbearing.
 3. The preloaded pivot joint assembly of claim 1 wherein asleeve member is positioned to isolate the elastomeric cushion from thestud pin portion.
 4. A preloaded pivot joint assembly comprising: ahousing having an axis; a stud having a part-spherical head portionretained within the housing, a shaft portion projecting axially from thehousing, and a pin portion projecting axially within the housing; and acompression spring disposed within said housing, said compression springbiasing one of said bearings against said part-spherical head portion toaccommodate axial forces therefrom, said compression spring furtherbiasing said pin portion to accommodate radial forces therefrom.
 5. Thepreloaded pivot joint assembly of claim 4 wherein said compressionspring is conical.
 6. The preloaded pivot joint assembly of claim 4wherein said compression spring is wound in an hourglass configuration,said narrowest portion of said compression spring contacting said pinportion.
 7. A preloaded pivot joint assembly comprising: a housinghaving an axis; a stud having a part-spherical head portion retainedwithin the housing, a shaft portion projecting axially from the housing,and a pin portion projecting axially within the housing; and a flaredtube disposed within said housing, said flared tube biasing one of saidbearings against said part-spherical head portion to accommodate axialforces therefrom, said flared tube further biasing said pin portion toaccommodate radial forces therefrom.
 8. The preloaded pivot jointassembly of claim 7 wherein said flared tube is conical.
 9. Thepreloaded pivot joint assembly of claim 7 wherein said flared tube hasan hourglass configuration, said narrowest portion of said flared tubecontacting said pin portion.
 10. The preloaded pivot joint assembly ofclaim 7 wherein said flared tube is composed of spring steel.
 11. Apreloaded pivot joint assembly comprising: a housing having an axis; astud having a part-spherical head portion retained within the housing, ashaft portion projecting axially from the housing, and a pin portionprojecting axially within the housing; at least one bearing havingpartially spherical bearing surfaces, said bearings retained within thehousing, said bearing surfaces enclosing a portion of saidpart-spherical head portion; a resilient annular member seated adjacentone of said bearings; and an elastomeric compliance bearing disposedwithin said housing, said compliance bearing biasing said resilientannular member against one of said bearings and said part-spherical headportion to accommodate axial forces therefrom, said compliance bearingfurther surrounding said pin portion to accommodate radial forcestherefrom.
 12. The preloaded pivot joint assembly of claim 11 whereinsaid elastomeric compliance bearing comprises an outer ring, and innerbearing sleeve, and an intermediate elastomeric layer disposed betweensaid outer ring and said inner bearing sleeve, said inner bearing sleevesurrounding said pin portion, and said outer ring contacting saidhousing.
 13. A preloaded pivot joint assembly comprising: a housinghaving an axis; a stud having a part-spherical head portion retainedwithin the housing, a shaft portion projecting axially from the housing,and a pin portion projecting axially within the housing; a slippersleeve disposed in said housing, said part-spherical head portion seatedwithin said slipper sleeve for rotation and angulation with respectthereto; a bearing having a part-spherical bearing surface, said bearingretained within said housing, said bearing surface enclosing a portionof said part-spherical head portion opposite said slipper sleeve; aresilient annular member seated adjacent said bearing; and anelastomeric compliance bearing disposed within said housing, saidcompliance bearing biasing said resilient annular member against saidbearing and said part-spherical head portion to accommodate axial forcestherefrom, said compliance bearing further surrounding said pin portionto accommodate radial forces therefrom.
 14. A preloaded pivot jointcomprising: a housing having an axis; a stud shaft having apart-spherical portion contained within said housing, a body portionextending axially from said housing, and a pin portion projectingaxially within said housing; at least one bearing component disposedwithin said housing adjacent said part-spherical portion of said stud totransfer axial loads from said shaft to said housing; and a resilientmember surrounding said pin portion to transfer radial forces fromangulation loads on said shaft to said housing, said resilient memberfurther configured to transfer axial loads from said bearing componentto said housing.
 15. The preloaded pivot joint of claim 14 wherein saidresilient member is isolated from said pin portion by a sleeve member.16. A preloaded pivot joint assembly comprising: a housing having anaxis; a stud having a lower part-spherical head portion and a flatradial upper surface retained within the housing, a shaft portionprojecting axially from the housing, and an elongated pin portionprojecting axially from said flat radial upper surface within thehousing; a bearing having part-spherical bearing surface, said bearingretained within the housing, said bearing surface enclosing a portion ofsaid lower part-spherical head portion; and a resilient member disposedwithin said housing, said resilient member biasing against said flatradial upper surface of said stud to accommodate axial forces therefrom,said resilient member further biasing against said elongated pin portionto accommodate radial forces therefrom.
 17. The preloaded pivot jointassembly of claim 16 wherein said resilient member is at least onecrinkled-coil compliance bearing.
 18. The preloaded pivot assembly ofclaim 17 wherein said at least one crinkled-coil compliance bearingincludes a plurality of radially aligned peaks and valleys.
 19. Thepreloaded pivot assembly of claim 18 wherein said at least onecrinkled-coil compliance bearing is spiral wound about said elongatedpin portion.
 20. The preloaded pivot joint assembly of claim 16 whereinsaid resilient member is an elongated elastomeric cushion.
 21. Thepreloaded pivot joint assembly of claim 20 wherein said elongatedelastomeric cushion is sized for an interference fit between saidhousing and said elongated pin portion of said stud.
 22. The preloadedpivot joint assembly of claim 16 further including an annular preloadmember disposed between said resilient member and said biased flatradial surface of said stud.